Yelp tumbles, Topeka worried about competition from Facebook

On a rough day for Internet momentum stocks, Yelp (YELP-7.6%) is the biggest decliner. A Topeka note raising concerns about Facebook's efforts to encroach on Yelp's turf could be playing a role.

Worries about competition from Facebook are nothing new for Yelp; shares fell hard earlier in January after Facebook showed off Graph Search, and more moderately the prior month after Facebook updated its Nearby feature to provide a list of local businesses a user might be interested in.